- You may be looking for nitrogen.
Nitro-9 was a powerful explosive created by Ace: a variant of nitroglycerin which she put in deodorant cans. (TV: Dragonfire, Remembrance of the Daleks, Battlefield) Further variants made by her were Nitro-9a (PROSE: Timewyrm: Exodus) and Neo-Nitro. (PROSE: Shadowmind) Nitro-12 was possessed by UNIT. (AUDIO: Vanguard)
Kevin put together a "backup plan" including dynamite and nitroglycerin; Caitlin Wallace responded by saying now she knew he was insane. When under attack by a Rat King, the Fifth Doctor threatened that he had nitroglycerin in Kevin's bag. The Doctor later revealed that he had left the nitro back in the tunnel, but had not yet disposed of it properly. (AUDIO: Rat Trap)